Damage buildup in Si under bombardment with MeV heavy atomic and molecular ions

Accumulation of structural disorder in Si bombarded at −196 °C with 0.5 MeV ²⁰⁹Bi₁ and 1 MeV ²⁰⁹Bi₂ ions (the so-called molecular effect) is studied by Rutherford backscattering/channeling spectrometry. Results show that the damage buildup is sigmodal even for such heavy-ion bombardment at liquid nitrogen temperature. This strongly suggests that, for the implant conditions of this study, the buildup of lattice damage cannot be considered as an accumulation of completely disordered regions. Instead, damage-dose curves are well described by a cascade-overlap model modified to take into account a catastrophic collapse of incompletely disordered regions into an amorphous phase after damage reaches some critical level. Results also show that Bi₂ ions produce more lattice damage than Bi₁ ions implanted to the same dose. The ratio of lattice disorder produced by Bi₂ and Bi₁ ions is 1.7 near the surface, decreases with depth, and finally becomes close to unity in the bulk defect peak region. Parameters of collision cascades obtained using ballistic calculations are in good agreement with experimental data. The molecular effect is attributed to a spatial overlap of (relatively dense) collision subcascades, which gives rise to (i) nonlinear energy spike processes and/or (ii) an increase in the defect clustering efficiency with an effective increase in the density of ion-beam-generated defects.Research at StPSTU was supported in part by the Ministry for General and Professional Education of the Russian Federation

КОНЦЕПЦІЯ МОБІЛЬНОЇ ЛАБОРАТОРІЇ КОМПЛЕКСНОЇ ОЦІНКИ ТА ПРОГНОЗУВАННЯ НАДЗВИЧАЙНИХ СИТУАЦІЙ

The concept of elaboration of mobile laboratories of integrated assessment and forecasting of emergency situations was developed. They provide operational radiation control in routine and emergency situations, remote and contact monitoring of concentration of harmful chemical contaminants in the atmosphere, soil, water, food, forage, etc. High technology equipment in theselaboratories enables to carry out assessment of the integral man-made and natural risks, to anticipate arising and development of emergency situations promptly, to forecast development and implementation of priority measures, to mitigate and eliminate potential effects of accidents and disasters.Розроблена концепція зі створення мобільних лабораторій комплексної оцінки та прогнозування надзвичайних ситуацій, які забезпечать оперативний радіаційний контроль в штатних і аварійних ситуаціях, дистанційний і контактний контроль концентрацій шкідливих хімічних домішок в атмосфері, ґрунті, воді, продуктах харчування, кормах та ін. Наукомістка апаратура таких лабораторій дає можливість проводити інтегральну оцінку техногенних і природних ризиків, прогнозувати виникнення та розвиток надзвичайних ситуацій, оперативно здійснювати розробку і впровадження першочергових заходів з ліквідації та пом'якшення можливих наслідків аварій і катастроф

Association between antiarrhythmic, electrophysiological and antioxidative effects of melatonin in ischemia/reperfusion

Melatonin is assumed to confer cardioprotective action via antioxidative properties. We evaluated the association between ventricular tachycardia and/or ventricular fibrillation (VT/VF) incidence, oxidative stress, and myocardial electrophysiological parameters in experimental ischemia/reperfusion under melatonin treatment. Melatonin was given to 28 rats (10 mg/kg/day, orally, for 7 days) and 13 animals received placebo. In the anesthetized animals, coronary occlusion was induced for 5 min followed by reperfusion with recording of unipolar electrograms from ventricular epicardium with a 64-lead array. Effects of melatonin on transmembrane potentials were studied in ventricular preparations of 7 rats in normal and ?ischemic? conditions. Melatonin treatment was associated with lower VT/VF incidence at reperfusion, shorter baseline activation times (ATs), and activation-repolarization intervals and more complete recovery of repolarization times (RTs) at reperfusion (less baseline-reperfusion difference, ΔRT) (p < 0.05). Superoxide dismutase (SOD) activity was higher in the treated animals and associated with ΔRT (p = 0.001), whereas VT/VF incidence was associated with baseline ATs (p = 0.020). In vitro, melatonin led to a more complete restoration of action potential durations and resting membrane potentials at reoxygenation (p < 0.05). Thus, the antioxidative properties of melatonin were associated with its influence on repolarization duration, whereas the melatonin-related antiarrhythmic effect was associated with its oxidative stress-independent action on ventricular activation.Fil: Sedova, Ksenia A.. Czech Technical University In Prague; República ChecaFil: Bernikova, Olesya G.. Ural Branch of Russian Academy of Sciences; RusiaFil: Cuprova, Julia I.. Czech Technical University In Prague; República ChecaFil: Ivanova, Alexandra D.. Lomonosov Moscow State University; RusiaFil: Kutaeva, Galina A.. Pitirim Sorokin Syktyvkar State University; RusiaFil: Pliss, Michael G.. Almazov National Medical Research Centre; RusiaFil: Lopatina, Ekaterina V.. University of Saint Petersburg; RusiaFil: Vaykshnorayte, Marina A.. Ural Branch Of Russian Academy Of Sciences; RusiaFil: Diez, Emiliano Raúl. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Medicas. Instituto de Fisiologia; ArgentinaFil: Azarov, Jan E.. Ural Branch of Russian Academy of Sciences; Rusia. Pitirim Sorokin Syktyvkar State University; Rusi

System for wireless power transfer

Поступила: 15.02.2021. Принята в печать: 10.03.2021.Received: 15.02.2021. Accepted: 10.03.2021.Рассмотрены вопросы беспроводной передачи энергии на малые расстояния. Подход может быть применим для беспроводной зарядки батарей беспилотных транспортных средств. Предлагается для передачи энергии использовать технику микрополосковых структур. При приближении микрополосковых структур друг к другу с лицевой части они образуют направленный ответвитель на симметричных полосковых линиях. Длина линий взаимодействия выбирается в несколько раз большей, чем четверть длины волны. Балластные сопротивления из схемы исключаются. Такой подход приводит к малым потерям передачи энергии при изменении расстояния между микрополосковыми структурами в широких пределах. Осуществлено моделирование работы системы передачи энергии, изготовлен экспериментальный образец и проведены экспериментальные исследования. Моделирование и эксперимент хорошо согласуются друг с другом.The issues of wireless power transfer over short distances are considered. The approach may be used for wireless charging of batteries in unmanned vehicles. It is proposed to use the technique of microstrip structures for power transfer. The microstrip structures form a directional coupler on symmetrical strip lines when approaching by front parts. The length of the interaction lines is chosen several times longer than a quarter of the wavelength. Ballast resistors are excluded from the circuit. This approach leads to small losses of power transfer when the distance between microstrip structures changes over a wide range. Modeling of the operation of the power transfer system has been carried out, an experimental sample has been made and experimental studies have been carried out. The simulation and experiment are well accorded.Работа выполнена при поддержке РФФИ и Севастопольского региона, проект № 20-48-920001.The research is carried out with the financial support of the RFBR and the Sevastopol region, project № 20-48-920001

nnovative Seasonal Migrations and Subsistence System of the Mobile Pastoralists of the Desert-Steppe Zone of Eurasia:role of social groups

The study of the economic system of the earliest nomads which inhabited the Eurasian desert-steppe belt in 5000-2000 is a relevant task of contemporary studies. The data on the organization of living space and the role of social groups of early prehistoric pastoralists in the exploitation of open steppe resources are scarce. The paper presents a new methodological approach to searching camps of the earliest pastoralists. The application of this approach enabled the archaeologists to discover numerous seasonal camps in the Sal-Manych Ridge located in the western part of the Eurasian steppes, including Eneolithic camps dated to 4200-3600 BC. The study of the occupation layers at the sites, evaluation of the productivity of pasture systems made it possible to categorize such sites as short-term seasonal camps occupied by pastoralists, evaluate the role of social groups in the organization of innovative seasonal migrations and reconstruct their subsistence system. The camps emerged as a result of developing pastoral economic strategy in the Lower Don region and the abutting areas reflecting the role of special social groups of pastoralists who managed to organize seasonal moves and address the issue of exploiting pastures located beyond the permanently occupied area

Optimal values of rovibronic energy levels for triplet electronic states of molecular deuterium

Optimal set of 1050 rovibronic energy levels for 35 triplet electronic states of $D_2$ has been obtained by means of a statistical analysis of all available wavenumbers of triplet-triplet rovibronic transitions studied in emission, absorption, laser and anticrossing spectroscopic experiments of various authors. We used a new method of the analysis (Lavrov, Ryazanov, JETP Letters, 2005), which does not need any \it a priory \rm assumptions concerning the molecular structure being based on only two fundamental principles: Rydberg-Ritz and maximum likelihood. The method provides the opportunity to obtain the RMS estimates for uncertainties of the experimental wavenumbers independent from those presented in original papers. 234 from 3822 published wavenumber values were found to be spurious, while the remaining set of the data may be divided into 20 subsets (samples) of uniformly precise data having close to normal distributions of random errors within the samples. New experimental wavenumber values of 125 questionable lines were obtained in the present work. Optimal values of the rovibronic levels were obtained from the experimental data set consisting of 3713 wavenumber values (3588 old and 125 new). The unknown shift between levels of ortho- and para- deuterium was found by least squares analysis of the $a^3\Sigma_g^+$, $v = 0$, $N = 0 \div 18$ rovibronic levels with odd and even values of $N$. All the energy levels were obtained relative to the lowest vibro-rotational level ($v = 0$, $N = 0$) of the $a^3\Sigma_g^+$ electronic state, and presented in tabular form together with the standard deviations of the empirical determination. New energy level values differ significantly from those available in literature.Comment: 46 pages, 9 picture

СИСТЕМА КОРРЕКЦИИ СЛУХА НА МОБИЛЬНОЙ ВЫЧИСЛИТЕЛЬНОЙ ПЛАТФОРМЕ

An implementation of digital hearing aid based on the mobile computing platform iPhone is proposed. The developed signal processing scheme has a low delay, takes into account characteristics of the computing platform and allows to perform the correction of sensorineural hearing loss. The cor-rection is carried out by linear frequency-dependent amplification and wideband dynamic range com-pression of the signal. In order to take into consideration magnitude characteristic of loudspeakers, the audiometry is performed using iPhone directly. The experimental results of with proposed hearing aid are given.Предлагается реализация цифрового слухового аппарата на основе мобильной вычислитель-ной платформы iPhone. Рассматривается схема обработки сигнала с малой алгоритмической за-держкой, позволяющая выполнять коррекцию слуха при нейросенсорной тугоухости и учитывающая особенности вычислительной платформы. Схема позволяет выполнять компенсацию потери слуха путем линейного частотно-зависимого усиления и широкополосной компрессии динамического диапа-зона сигнала. Для учета амплитудно-частотных характеристик динамиков гарнитуры аудиометрия выполняется непосредственно при помощи iPhone. Приводятся результаты экспериментального ис-следования реализованного слухового аппарата

Электронно-микроскопические изменения слизистой оболочки носоглотки у пациентов с COVID-19 в зависимости от клинической формы и периода заболевания

Given that COVID-19 is a global public health problem and that almost all countries in the world have been severely affected by the COVID-19 pandemic, research is being actively pursued to better understand the effects of the virus on human cells. However, it is not clear what changes are observed in the cells of the main gate of infection – the mucosa of the mouth and the nose at different clinical forms and at different periods of disease. Understanding the ultra-structural cell changes of SARS-CoV-2 targets may help clarify the pathogenic aspects of infection in the lower respiratory tract. In this study, the elements of the life cycle of SARS-CoV-2 virus in the cells of the respiratory epithelium of the nose in patients with COVID-19 were evaluated using electron microscopy for the purpose of detecting the peculiarities of viral activity depending on the form and period of disease. Bioptats of the nasal mucous membrane were taken from COVID-19 patients and subsequently examined by electron microscopy. The severity of structural changes in tissue samples, presence of SARSCoV-2 virus in cells were determined, then bioptats were grouped according to the clinical form of the infection process (inapparent, acute upper respiratory tract infections, viral lung disease) and period of disease. It has been established that the most characteristic changes in the mucous membrane of the nose were observed in the first week of infection caused by SARS-CoV-2 and occurring in the form of acute respiratory disease, while viral lung infections have had the highest virus density in vesicles within cells, the formation of smooth virus-free vesicles is most common in inapparent forms. The data obtained may indicate that the formation of classical virus-induced changes in the respiratory epithelium of the nose mucous (vesicles with viral particles and signs of their release from the cell) is characteristic of localized forms of infection caused by SARS-CoV-2 (respiratory infection of the upper respiratory tract) and in cases of generalized infection (viral infection of the lungs and probably other organs and systems) accumulation of the infectious agent in high concentrations in vesicles. Учитывая, что COVID-19 представляет общемировую проблему в области здравоохранения и почти все страны мира серьезно пострадали от пандемии COVID-19, активно проводятся исследования, направленные на лучшее понимание воздействия вируса на клетки организма человека. Вместе с тем, не до конца ясно, какие изменения наблюдаются в клетках основных ворот инфекции – слизистой рото-, носоглотки при разных клинических формах и в разные периоды заболевания. Понимание ультраструктурных изменений клеток-мишеней SARS-CoV-2, возможно, поможет уточнить патогенетические аспекты распространения инфекции в нижние дыхательные пути. В настоящем исследовании при помощи электронной микроскопии проведена оценка элементов жизненного цикла вируса SARS-CoV-2 в клетках реснитчатого эпителия носоглотки у пациентов с COVID-19 с целью выявления особенностей жизнедеятельности вируса в зависимости от формы и периода заболевания. У больных COVID-19 отбирались биоптаты слизистой оболочки носоглотки, которые в последующем исследовались при помощи электронной микроскопии. Определялась выраженность структурных изменений в образцах ткани, наличие вируса SARS-CoV-2 в клетках, далее биоптаты были распределены по группам в зависимости от клинической формы инфекционного процесса (инаппарантная, острое респираторное заболевание верхних дыхательных путей, вирусное поражение легких) и периода заболевания. Установлено, что наиболее характерные изменения слизистой оболочки носоглотки наблюдались в 1-ю неделю инфекции, вызванной SARS-CoV-2 и протекающей в форме острого респираторного заболевания, тогда как для вирусного поражения легких отмечалась наибольшая плотность вируса в везикулах внутри клеток, при этом образование гладких везикул, не содержащих вируса, наиболее характерно для инаппарантных форм. Полученные данные могут свидетельствовать, что формирование классических вирус-индуцированных изменений реснитчатого эпителия слизистой носоглотки (везикул с вирусными частицами и признаками их выхода из клетки) характерно для локализованных форм инфекции, вызванной SARS-CoV-2 (респираторной инфекции верхних дыхательных путей), а в случаях развития генерализованной инфекции (вирусного поражения легких и, вероятно, других органов и систем) – накопление возбудителя в высоких концентрациях в везикулах.